I was going to guess you were using firefox. I know exactly what you are talking about. I can have firefox on desktop. Have about 8-15 tabs open and all of sudden got a black screen. I too didn't have hardware accelerator enabled either. It didn't matter if firefox was up on screen or minimized. But it was so rare and it seem to correlate to having a lot tabs open that there was no way for me to reproduce it. I also just tested changing the Video Profile in Microsoft Edge (Youtube )and guess what? It works!!! it works just fine. I'm still missing the Custom feature though. It's a pretty big coincidence that I'm seeing this all relate to Firefox.